Average monthly snow and rainfall in O'Fallon (IL)
The mean monthly precipitation over the year in O'Fallon (Illinois), including rain, snow, hail.
- A lot of rain (rainy season) falls in the months: April, May, June, July and September.
- On average, June is the wettest month with 142 mm of precipitation.
- On average, January is the driest month with 56 mm of precipitation.
- The average amount of annual precipitation is 1171 mm.
Forecast for O'Fallon (IL)
partly cloudy and no rain
almost clear and no rain
broken clouds and thunder